US2383982A - Control mechanism - Google Patents

Description

Sept. 4, 1945. H. E. MALONE CONTROL MECHANISM INVENTOR. HUMER EMALUNE W? wTTORNEY.

2 Sheets-Sheet l l 4 9 l Y B c m a m w m 1 & n a 1 F 8 .l 3 m 8 WW 9 5 8 o w 5 BIHETAL Sept. 4, 1945. H. E. MALONE 2,383,982

' CONTROL MECHANISM Filed Dec. 26, 1941 2 Sheets-Sheet 2 INVENTOR.

BY HUMER E- MALONE WF$s ATTORNEY.

Patented Sept. 4, 1945 CONTROL MECHANISM Homer E. Malone, Milwaukee, Wis., assignor to Perfex Corporation, Milwaukee, Wis., a corporation of Wisconsin Application December 26, 1941, Serial No. 424,395

12 Claims.

This invention relates in general to automatic controls and more particularly to controls of the type adapted for wall mounting. It is an object of this invention to provide a wall mounting automatic control instrument which is simple and rugged in construction, which is neat and attractive in exterior appearance, which may be easily installed, and which provides for protection of the various working parts thereof.

More particularly, it is an object of this invention to provide a wall mounting automatic control instrument in which all of the parts are secured to the inside of the cover, thus forming a single control unit in which the cover serves as a base, the cover also serving to insure protection of the working parts of the instrument prior to and during installation of the instrument.

A further object of the invention is the provision of a wall mounting thermostat in which transmission of heat from the wall to the thermal element by conduction is reduced to a minimum, thus rendering the control more quickly responsive to changes in air temperature.

Another object of the invention is the provision of a simple adjusting mechanism for permitting a manual adjusting member to be spaced from the mechanism operated thereby.

Other objects of the invention will become apparent from the following description and appended claims.

For full disclosure of this invention, reference is made to the following detailed description and to the accompanying drawings, in which Fig. l is a side view, partly in section, of a room thermostat embodying the present invention;

Fig. 2 is a rear view partly in section;

Fig. 3 is a. sectional view taken on line 3-3 of Fig.2;

Fig. 4 is a front view of the sub-base member:

Fig. 5 is a front view of the wall plate, and showing the cover in section;

Fig. 6 is a front view of the thermostat cover;

Fig. '7 is a sectional view taken on line 1-1 of Fig. l; and in which Fig. 8 is a fragmentary sectional view showing the differential adjustment mechanism.

Referring now to Figs, 1 and 5, reference character l indicates a wall plate having rearwardly projecting bosses 2 for spacing the wall plate from the wall upon which it is mounted by suitable screws which extend through these bosses. The wall plate is off-set at 3 to provide an upper off-set portion 4 having a wide U-shaped opening 5 therein. This upp r portion 4 has its legs 6 and I on opposite sides of opening 5 bent inwardly at 8 and 9 for engaging the wall and steadying the wall plate thereon. The upper section 4 of the wall plate also carries a terminal panel in of insulating material, this terminal panel having an opening I l at its top for permitting wires extending from the wall to be brought to the front of the panel. The terminal panel III also carries a pair of contact brackets l2 and I! having flexible, downwardly and outwardly extending contact arms M and I5, and terminal screws l6 and H. Th terminal panel III also carries a pair of stop members l8 and I9, these stop members extending through openings in the spring members it and I5 and having head portions which limit movement of the spring members away from the wall plate.

Mounted on the ,wall plate I is a cover 20 for the instrument, this cover having a front wall 2 I, side walls 22 and 23, and end walls 24 and 25, the end walls being provided with openings 28 and 21 for permitting air in the room to circulate through the cover. The upper end of the cover may be held in place by spring members 28 and 29 which are attached by suitable brackets to the wall plate and which engage the rear face of opening 26. The lower end of the cover 20 may be secured to the wall plate I by means of an ear 30 formed on the wall plate and receiving a screw 3| which passes through an opening in the bottom of the cover.

When the present invention is embodied in room thermostat construction, it is preferable to provide the cover with a slot 32 for receiving a thermometer element 33 which is mounted on the rear of the cover by a spring member 34 secured to the cover by screw 35.

Mounted within the cover 20 is a sub-base 38, this sub-base being spaced from the front wall of the cover by means of bosses 39 formed on the front of the cover adjacent the side walls, these bosses receiving screws 4| and 42 which pass through sub-base 38. The sub-base 38 is also steadied inside of the cover by additional bosses 43 and 44 located above bosses 39. This arrangement in which the sub-base is supported only at its mid-portion in the cover avoids distortion of the sub-base when screwed tightly to the cover.

The sub-base 38 is preferably of molded construction, its front face being hollowed out as at 45. The rear face of the sub-base is provided with a boss near its mid-portion, this boss carrying a spring hinge 46 which is clamped thereto by a clamping plate 41. The other end of the spring hinge clamped between a U-shaped bimetal element as and an adjusting arm 48 having slotted end receiving a calibrating screw :38 which rides upon a helical cam member The U-shaped bimetal element 48 at its upper end carries an armature bracket 52. Between the armature bracket 52 and element 48 is clamped a pin 53 carrying a twin contact bracket ti l, this pin being steadied at its upper end by an inwardly bent portion of the armature bracket. The twin contact bracket 54 carries a rigid arm 55 intermediate its ends, this arm 85 having an off-set portion and carrying a movable contact 55 at one end. The arm 85 also carries a flexible arm 51 which at its other end carries a second movable contact 58/ The movable contacts 58 and 58 cooperate respectively with fixed contact studs 8! and 62 which are mounted upon the sub-base 38. This sub-base also carries a permanent magnet 83 which is secured thereto by means of a screw 64 extending from the front of the sub-base and engaging a clamping plate 85. The clamping plate 41 for the spring hinge carries a heater 88 which is engaged by a slider 61 carried by the clamping plate 85 for the permanent magnet. It will be apparent that the thermostatic element 48 serves to actuate the control means comprising the fixed and movable contacts upon change in temperature, the snap action means, consisting of the permanent magnet and armature, imparting snap action to the engagement and disengagement of the contacts. '11; will also be apparent that rotation of the helical cam it will vary the control point of the instrument. No novelty is claimed in the particular construction of the thermostatic element, twin contact construction, or adjustable heater construction, this general arrangement being shown in the Lindemann Patent 2,250,135, dated July 22, 1941. For a. more complete description of the construction and operation of the bimetal element and switching mechanism, reference is made to this Lindemann patent.

The fixed contact stud 62 is carried by a bracket '18 mounted upon the sub-base, this bracket being generally L-shaped and including a leg H which extends rearwardly into engagement with the contact spring l8 carried by the wall plate I. Thus when the thermostat cover is in place on the wall plate the terminal screw [1 is electrically connected to the fixed contact stud 82.

The fixed contact stud 8| is carried by a bracket 18 which is joined to the clamping member 85 of the permanent magnet by an outwardly extending portion 18. Thus the contact stud 8| is electrically connected with the slider 81 which is mounted on member 88 and which engages the heater 88. The heater 88 is electrically insulated from the clamping plate 41 and is connected electrically to a bracket 11 which is mounted on the sub-base 38, this bracket having a rearwardly extending leg I8 which engages the spring blade I4 when the cover is in place on the wall plate. Thus when the movable contacts 88 and 58 are in engagement with their respective fixed contact studs, a circuit is completed from the terminal screw I! through spring member l5, contact leg 1|, stud 82, movable contact 88, flexible arm 51, movable contact 58, contact stud 8|, bracket 1!, connecting member 18, clamping plate 88, wiper 61, heater 88, bracket 11, connector leg 18 and spring blade I to terminal screw I8. When the movable contacts are Q18- shaft.

engaged from the fixed contacts, the above traced circuit is of course broken.

The helical cam member 5| is preferably formed of insulation material and is secured to a shaft which extends through a hole formed in the sub-base 38 and also through an enlarged hole 8! in the front wall of the cover. The front end of the shaft 88 is slotted as at 82 and carries a control point adjusting knob 88 which extends through the opening Ill. The knob 83 is formed with a flattened, rearwardly projecting portion 84 which fits into the slot 82 in the shaft 80. This insures that the knob 83 must be positioned correctly on the shaft 88 so that the pointer 88 (Fig: 6) will be positioned properly with respect to the helical cam 5|. The pointer 85 on the knob 83 cooperates with indicia 86 carried by the cover for indicating the control point setting of the instrument. The knob 88 is fastened to the shaft 80 by means of a set screw 81 which serves to spread the split section of the shaft into tight engagement with the knob. Preferably the helical cam 5| is formed at its rear to receive a disc 88 which is held in snug engagement between the cam and sub-base by a spring member 88. The disc 88 cooperates with a lug 80 mounted on the rear of the sub-base by a screw 8| for forming a lock to prevent unauthorized persons from changing the control point adjustment of the instrument. It will be apparent that when the screw 8| is tightened, the lug 88 will prevent rotation of the disc 88, which in turn prevents rotation of the cam 5|. When the screw 8! is loosened the helical cam 5! is free to rotate.

It is desirable to provide for adjusting the duration of the "on periods of the thermostat. Preferably this adjustment should be accessible to the home owner so that he may vary the "on periods to secure optimum control without requiring any knowledge of the instrument mechanism. To obtain this result, the fixed contact stud 82 is threaded loosely into the bracket 18. It will be apparent that rotation of the stud 82 will move the fixed contact in and out and thus vary the distance between the armature and magnet when the contacts are engaged. This varies the amount of force required to be built up within the thermostatic element before the contacts are disengaged. Inasmuch as it requires time for the heater 88 to build up an opening force within the thermostatic element, it follows that adjustment of the stud 82 varies the thermostat on period. The outer end of the stud 62 is attached to a lever 82 by a screw as shown. Preferably a spring 88 surrounds the stud 82 for resisting rotation thereof, thus tending to retain the stud 82 in adjusted position. The free end of the lever 82 is attached to a. link 84, the other end of which is attached to a second lever 88. The lever 88 is slotted at 88 and fits over a coinciding portion formed on a shaft 81 which extends through the sub-base 88. The link 85 may be held onto the shaft 81 in any suitable manner as by peening. The shaft 8'! is formed with a screw head at its inner end. Its other end is formed slightly flattened as at 88 and receives an adjusting knob 88 which extends through an opening in the front of the cover. The knob 88 is provided with an opening which flts tightly on the portion 88 of the shaft 81, this opening being flattened similar to the portion 88 so as to insure proper positioning of the knob on the Preferably the knob 88 is held on the shaft by friction, the shaft being splined at its end. The knob 88 canies a pointer [88 which ing an opening for such knob. The differential adjustment may then be actuated by removing the cover from the wall plate and rotating the shaft 91 with a screw driver. Preferably the subbase 38 is provided with indicia ill! for indicatin the differential adjustment.

From the foregoing description it will be apparent that the wall plate I is formed so as to be spaced from the wall so as to reduce conduction of heat between the wall plate and wall to a minimum. It will also be seen that the only metallic heat path from the wall plate to the bimetal element consists of the spring contact members II and I and the contact legs or brackets Ii and 78. This path for heat conduction is very long and of very small cross-sectional area. As a result, conduction of heat between the wall or wall plate and the thermostatic element is reduced to a minimum. This permits the thermostatic ele- I ment 48 to follow changes in room temperature more rapidly than if the element were in better heat conducting relationship with the wall, As a result the arrangement provided by this invention provides a more sensitive wall mounting control.

It should also be apparent that the instrument provided by the present invention is very easy to install. All that is required is the mounting of the wall plate on the wall and connection of the control wires to the terminal screws, the thermostat cover then being secured in place on the wall plate for completing the installation. It should further be apparent that all of the working parts of the instrument are at all times completely within the cover and consequently protected by the cover. This insures against possible damage to the instrument during installation. It will be further apparent that the present invention provides a construction which is neat and attractive in exterior ap arance, and which may be readily replaced if necessary.

While I have shown and described a preferred form of the invention, it is obvious that many changes may be made from the device disclosed without departing from the invention. Accordingly it is desired to be limited only by the scope of the appended claims.

What is claimed is:

1. In a control device for mounting on a wall. the combination of, a wall plate carrying termi nals for electrical wiring and adapted to be mounted on a wall, a cover for the control device adapted for mounting on said wall plate, an elongated sub-base mounted on the inside of the cover and being attached to said cover only near the mid-portion of said sub-base, a condition responsive switching mechanism secured to said sub-base, and means for securing the cover directl to the Wall plate independently of the sub-base and for connecting the switching mechanism to the terminals on said wall plate.

2. In a control device for mounting on a wall, the combination of, a wall plate carrying terminals for electrical wiring and adapted to be mounted on a wall, a cover for the control device adapted for mounting on said wall plate, a sub-base mounted on the inside of the cover having one side facing the rear face of the cover and its other side facing the wall plate, a condition responsive device on the side of the sub-base facing the wall plate, said condition responsive device havin one portion thereof secured to the sub-base and actuating a first electrical contact, a. contact bracket secured to the sub-base and carrying a second electrical contact arranged for cooperation with said first contact, said contact bracket including an electrical conducting portion extending toward the wall plate, a second bracket mounted on said sub-base and having an electrical conducting portion electrically connected to said first contact and extending toward said wall plate, and resilient contact means on the wall plate arranged for engagement with said brackets and connected to said terminals.

3. In a control device for mounting on a wall, the combination of, a wall plate carrying terminals for electrical wiring and adapted to be mounted on a wall, a cover for the control de-- vice, means for securing the cover directly to said wall plate, a pair of stationary contacts mounted on the inside of the cover, means including condition responsive means mounted on the inside of the cover for electrically bridging or unbridging said stationary contacts, a first bracket mounted on the inside of the cover, said bracket carrying one of said stationary contacts and extending toward the wall plate, a second bracket carrying the other stationary contact and extending toward the wall plate, and resilient contact means on the wall plate, said contact means being connected to said terminals and arranged for engagement with said brackets when the cover is in place on the wall plate.

4. In a control device for mounting on a wall, the combination of, a wall plate carrying terminals for electrical wirin and adapted to be mounted on a wall, a cover for the control device adapted for mounting on said wall plate, a

sub-base mounted on t e inside of the cover having one side f acing the rear face of the cover and its other side facing the wall plate, a condition responsive device on the side of the sub-base facing the wall plate, said condition responsive device having one portion thereof secured to said sub-base and actuating a movable electrical contact, a fixed contact carried by the sub-base for cooperating with said movable contact, first adjusting means extending through the cover for permitting adjustment of the fixed contact from outside the cover, second adjusting means ex tending through the cover for shifting the condition responsive device on the sub-base, and means for securing the cover to the wall plate and for connecting the contacts to the terminals on the wall plate.

5. In a control device for mounting on a wall, the combination of, a cover adapted to be mounted on the wall, a sub-base mounted on the inside of the cover having one side facing the rear face of the cover and its other side facing the wall, a condition responsive device mounted on the side of the sub-base facing the wall and actuating an electrical contact, a stationary contact mounted on the sub-base and cooperating with.

the first mentioned contact. first adjusting means extending through the cover for permitting adjustment of the fixed contact from outside of the cover, and second adjusting means extending through the cover for shifting the condition responsive means on the sub-base.

6. In a control device for mounting on a wall, the combination of, a cover adapted to be mounted on the wall, a sub-base mounted on the inside of the cover having one side facing the rear face of the cover and its other side facing the wall, a condition responsive device mounted on the side of the sub-base facing the wall and actuating an electrical contact, a stationary contact mounted on the sub-base and cooperating with the first mentioned contact, and adjusting means for the control device, saidadjusting means comprising a shaft extending through the cover and rotating a first a second shaft for posi-v tioning a portion of the control device and being rotated by a second lever, and a link connecting said levers, said link yieldably engaging the subbase for holding the parts in adjusted position.

7. In a control device for mounting on a wall, the combination of, a cover adapted to be mounted on a wall, a condition responsive device mounted on the inside of the cover, a rotatable member for adjusting the control device, a first lever for rotating said member, a rotatable adjusting member mounted on the cover and extending through the cover, a second lever rotated by said adjusting member, and a link for connecting said two levers.

8. In a control device for mounting on a wall, the combination of, a cover adapted to be mounted on a wall, a condition responsive device mounted on the inside of the cover, a rotatable member for adjusting the control device, a first lever for rotating said member, a rotatable adjusting member mounted on the cover and extending through the cover, a second lever rotated by said adjusting member, and a link for connectingsaid two levers, said link being resilient and having a surface thereof yieldably urged against a stationary surface for holding the parts in adjusted position.

9. In a control device, a base member, a condition responsive device mounted on the base member, a rotatable member for adjusting the control device, a first lever for rotating said rotatable member, a rotatable adjusting member mounted on the base member, a second lever rotated by said adjusting member, and a link for connecting said two levers, said link yieldably engaging a relatively stationary surface for holding the parts in adjusted position.

10. In a control device for mounting on a wall, the combination of, an elongated cover adapted to be mounted on the wall, a thermostatic element having one portion thereof mounted on the back of the cover, switching mechanism mounted on the back of the cover and controlled by said thermostatic element, a first adjusting means at one end of the cover and extending therethrough, said first adjusting'means including a rotatable member accessible from the front of the cover and varying the control point of the device, a second adjusting means at the other end of the cover and extending therethrough, said second adjusting means varying the effective differential of the instrument and including a second rotatable member accessible from the front of the cover.

11. In a control device for mounting on a wall, the combination of, an elongated cover adapted to be mounted on the wall, a thermostatic element having one portion thereof mounted on the back of the cover, a movable contact actuated by the thermostatic element, a fixed contact cooperating with said movable contact, means including a helical cam mounted on the cover and facing the wall for adjusting the control point of the instrument, and an operating member for rotating said helical cam, said operating member extending through the front of cover so as to be accessible from the front thereof.

12. In a control device for mounting on a wall, the combination of, an elongated cover adapted to be mounted on the wall, a thermostatic element having one portion thereof mounted on the back of the cover, a movable contact actuated by the thermostatic element, a fixed contact cooperating with said movable contact, means including a helical cam mounted on the cover and facing the wall for adjusting the control point of the instrument, an operating member for rotating said helical cam, said operating member extending through the cover so as to be accessible from the front thereof, means for adjusting said fixed contact to vary the operating differential of the control device, said last mentioned means including a second operating member extending through the cover.

HOMER E. MALONE.

Images